Surgical suture. Surgical suture is a medical device used to hold body tissues together after an injury or surgery. Application generally involves using a needle with an attached length of thread. A number of different shapes, sizes, and thread materials have been developed over its millennia of history.
Parentheses or round brackets, denoted by '( )', is generally used to define the different precedence of numbers in a mathematical expression. Box brackets or square brackets: Apart from mathematical expression, '[ ]' square brackets are also used to represent the numbers in interval.
Parenthesis is of course Greek and means in fact insertion. It has taken the meaning of the signs  (  or  ) . Parentheses is the regular plural. Usually, you use a pair of the signs showing an insertion, then between parentheses - or brackets ; however, in parenthesis means : as an afterthought. A parenthesis is one of the marks usually called (ordinary, or curved) brackets in the UK or material set off by a pair of brackets (or commas or dashes). I've just used four parentheses to enclose two parentheses â but I wouldn't usually mix senses like this as it gets too confusing.